ByDAVID A. LIEB, Associated PressFebruary 8, 2012

Alyssa Bustamante is escorted out of the Cole County Courthouse, in Jefferson City, Mo. on Wednesday, to a waiting sheriff's vehicle. Bustamante, who had described the slaying of a young neighbor girl as an “ahmazing” thrill made an emotional apology Wednesday to the girl’s family and was sentenced to a potential lifetime in prison.

A Missouri teenager who had described the slaying of a young neighbor girl as an "ahmazing" thrill made an emotional apology Wednesday to the girl's family and was sentenced to a potential lifetime in prison.

Moments before her sentence was imposed, 18-year-old Alyssa Bustamante rose from her chair — with shackles linking her ankles and holding her hands to her waist — and turned to face the family of 9-year-old Elizabeth Olten, whom she confessed to killing in October 2009.

"I really am extremely, very sorry for everything. I know words," she said, pausing to take a deep breath and struggling to compose herself, "can never be enough, and they can never adequately describe how horribly I feel for all of this."

She later added: "If I could give my life to get her back I would. I'm sorry."

Elizabeth's mother, Patty Preiss, who on the first day of Bustamante's sentencing hearing called her an "evil monster" and declared "I hate her," sat silently, staring forward as Bustamante's finished her apology.

Cole County Circuit Judge Pat Joyce then sentenced Bustamante to the maximum possible sentence for second-degree murder — life in prison with the possibility of parole. She ordered the teenager to serve a consecutive 30-year term for armed criminal action, a charge resulting from her use of a knife to slit the throat and stab Elizabeth after she had strangled her into unconsciousness.

Elizabeth's family left the courthouse without talking to reporters.

"The sentencing process was extremely difficult for the family, as no sentence can adequately punish this heinous crime," Matt Diehr, a St. Louis attorney speaking on behalf of the family, said later in a telephone interview.

Bustamante's family, which also was present in the courtroom, declined to comment about the sentence, though an attorney called it "harsh." There was no indication that Bustamante planned to appeal the sentence.

Bustamante originally had been charged with first-degree murder but pleaded guilty last month to the lesser charges to avoid a trial and the possibility of spending her life in an adult prison with no chance of release.

Cole County Prosecutor Mark Richardson said after Wednesday's sentencing that he agreed to the lesser charge because the judge had suppressed a statement given by Bustamante to authorities in which she described the slaying and stated she wanted "to know what it felt like" to kill someone.

Bustamante was 15 years old at the time of Elizabeth's murder in the small town of St. Martins, just west of Jefferson City. Evidence presented during her hearing revealed that Bustamante had dug a shallow grave in the woods several days in advance, then used her younger sister to lure Elizabeth out of her home with an invitation to play. Bustamante, who had hidden a knife in a backpack, said she had a surprise for Elizabeth in the forest. The surprise turned out to be her demise.

Defenses attorneys had argued for leniency after presenting evidence from family members and mental health experts about Bustamante's troubled childhood. Bustamante was born to teenage, drug-abusing parents; her father was imprisoned and her mother abandoned her, leaving her in the legal custody of her grandmother.

"This was a child who had been spiraling out of control, but has treatable conditions," Bustamante's attorney, Charlie Moreland, said after the sentencing.

But Richardson said the life sentence was justified. He described Bustamante as "a truly evil individual who strangled and stabbed an innocent child simply for the thrill of it."

Under Missouri guidelines, Bustamante would have to serve 35 years and five months in prison before she is eligible for parole, said Department of Corrections spokesman Chris Cline. It's also possible that the more than two years Bustamante spent in jail while awaiting her sentencing could be counted toward that time.

After spending several weeks at a diagnostic prison, Bustamante could be placed in either one of Missouri's two female prisons or sent out of state. Cline said department officials also would evaluate whether Bustamante should be kept separate from other adult woman inmates.